Antique fire sprinkler system.

[Don P]

I'm looking over an old building from the early 50's that has an extensive steel pipe fire sprinkler system that I believe has been off since the 70's. Before I call for scrapping it... I'm assuming from a corrosion standpoint it would be impossible to recommission such a thing?

[rusticretreater]

Depending on where water was left in the system, portions might need to be replaced.  A pressure test would show just how bad.  Heck, just turning on the water could tell you all you need to know. 

An inspector probably won't let a system that old pass muster.  There are also probably new regulations that will need to be met.   You would certainly need to remove the sprinkler heads and flush the system thoroughly.  Sounds messy. 

[Old Greenhorn]

Don, there are two basic types of systems. One is called a wet line system. These were full of water, with hopefully, sort sort of rust inhibitor while it just sat there. This design was replaced by a Dry Head System in which there was no water in the pipes (hopefully) for the life of the system. After construction and testing for leaks with air or gas, and detectors, the system is charged with either compressed air of gas (Like nitrogen). Then the water is connected to the fire pump and valving system. Once it's all in place the valves are connected and the water pressure pushes into a big vessel like an air hammer dampener.  SO the way it works is, water never enters the piping system until a sprinkler head pops and releases the air, which is then replace by the water behind it bringing water to the fire. The more heads that pop, the more water that flows in as the gas goes out. Putting it back into service means purging everything out and resetting as it was before, which is a fairly big job.
 I am not a fire engineer and only had the rudimentary training they gave us fire officers to understand how it works. I also did some walkthroughs on large building and a brand new prison which had a huge room to house the fire pumps and control systems, which were pretty complex.
 So, if you looked at a dry system, those pipes could be like new inside. Bet you didn't expect that. Just be careful when you first open a line.

[Old Greenhorn]

Here is an NFPA LINK to explain the basic difference. There may be enough in there for you to look at your system and make a good guess which you have.

[Don P]

Thanks, now I have an ANSI and a NFPA link from you open  . It was a wet system, I have seen one section that was removed and the pipe was left open/ uncapped. I'm meeting an engineer there Fri from a larger firm, I'll see who he knows. I'm not hopeful, it does cut into the occupant load unsprinklered. Although, it cuts the need for bathrooms in half, always a silver lining  .

[Old Greenhorn]

Yeah, the beauty of a dry system is that everything past the pump room requires almost zero maintenance. Wet systems, not so much, things rust out, leak, etc.
 I am not sure if you are looking to salvage this building or what. About 10 years ago they started pushing sprinkler system in residential and they had a special heat resistant PVC type pipe they use which was heat resistant. I thought, at the time, that it would just be a matter of time before that pipe started showing up in industrial applications because of cost. That too was a dry system.
 If it's 'on the border' I would call in a fire systems guy to look it over, they know what the new stuff can do for you and how much of it you could salvage. Assuming you find the 'right guy'.
 Best of luck.

[Southside]

Well at least it's not those old glass globes full of some strange liquid that you are supposed to throw at the fire.  I have a couple of those for collection sake.  You watch, now OG is going to come on here and tell me that is plutonium water in those globes...

[Old Greenhorn]

NAILED IT!
Those were called 'fire grenades' and early ones were filled with salt water, the better ones were filled with carbon tetrachloride which displaced the oxygen molecules in the air, in other words, smothered the fire as well as any people in the area.
I can say, that when a workbench goes up in flames in a small room and you spill over a can of carbon tet and close the door and walk out, in just a minute or two, that fire is out. or so I have heard.